The direction that an operator has little to no control over is side
swing. Do not allow anyone to ever stand on the side of ditch or
excavation to watch, no matter how long you have operated

This is an understatement. While not a pro, I have run my fair share
of "heavy" equipment. I was digging a trench to run phone, water, etc
to my new shop. I had a nice level trench going and was at the shop
end cleaning out the end of the trench. Swinging back to take a few
more scoops. Smack! Right into the side of my new steel. Blast. At
least at was primarily a relatively easy to replace edging piece, but
it still ticked me off at the time. I was being very conscientous to
not "overswing", but the momentum of the arm took it that one time and
slapped it right into the shed.

Side swing is usually very "quick" and unthrottled. The other controls
have much slower flows are very controllable. Side swing is usually a
faster move with little real control.

JW